A cable reel includes a flat cable constructed in a wound condition with a plurality of turns. The flat cable is fixed at its one end to a fixed member, and is also fixed at the other end to a movable member. The flat cable extends from both ends to the outside of the cable reel. When the movable member is rotated, the flat cable is wound up around the movable member, or it is unwound from the movable member. Thus, the movable member is allowed to be rotated by a predetermined amount. For example, the cable reel is used in a steering device for an automobile.
The flat cable as mentioned above is formed by laminating a plurality of conductor foils between a pair of flexible films such as polyethylene terephthalate (PET). In installing the cable reel in various equipment, e.g., the steering device as mentioned above, it is necessary to allow the flat cable to rotate in opposite direction about a neutral position by substantially the same amount. Further, considering possible erroneous mounting of the flat cable, a cutter is provided in the vicinity of a fixed portion of the flat cable to the fixed member, so that when the movable member is rotated by an amount greater than the predetermined amount, the flat cable is cut by the cutter to thereby prevent locking of the movable member due to the erroneous mounting of the cable reel.
Recently, an increase in the circuits to be connected through the flat cable have been proposed, and it has also been proposed that the cable reel be installed in as small a space as possible. To satisfy these proposals an arrangement that has been considered is that as many conductor foils as possible be arranged within a given width of the flat cable by reducing a pitch (spacing) between the adjacent conductor foils, or that the width of the flat cable be made as narrow as possible. However, if the pitch (spacing) between the adjacent conductor foils is excessively reduced, there is a possibility that the flexible films will peel from each other or that adjacent conductor foils will be short-circuited. As a result, the reliability of the cable reel will be remarkably reduced.